Wireless communications develop continuously. New communications systems entail and other may disappear. When establishing new communications systems, an operator providing commercial services normally wants to know whether the system as established provides expected or designed performance. Example wireless communications systems include radio communications systems and optical communications systems.
Cellular wireless communications systems provide a means of covering a surface with wireless communications resources. A surface to be covered by wireless services is divided into a number of smaller areas, cells, each cell being served by one or more base stations. With a great number of base stations, each base station providing services for a corresponding cell of service coverage, a great surface is covered. In case a wireless resource such as radio frequency spectrum is used repeatedly in more than one cell, a great service area can be covered also with a limited amount of the wireless resource. Today, there is a plurality of well known cellular radio communications system made available to the market, such as GSM (Global System for Mobile communications, CDMA 2000 (Code Division Multiple Access 2000), UMTS (Universal Mobile Telecommunications system), WiMax (Worldwide Interoperability for Microwave Access) and LTE (Long Term Evolution).
International Patent Application No. WO03047280 discloses a method of testing a digital mobile phone network comprising measurements on real traffic or created test traffic using a test mobile phone coupled to a computer. Measurements made by the computer are sent as traffic to create one or more data streams within the mobile phone network. Time data, for example derived from the network itself or from a GPS receiver may be included with the measurement data. In one embodiment, the test mobile communications device comprises an unmodified consumer mobile communications device. The method also comprises reading of signaling data and measurement data from different interfaces of a communications network infrastructure.
U.S. Pat. No. 6,294,961 provides selectable oscillation circuitry for switching between two communicating modes. Digital Cellular System, DCS, and Global System for Mobile Communications, GSM, both employ GMSK for modulating digital signals. A cellular phone is controlled so as to select and properly use one of two voltage-controlled oscillators in a cellular phone that can be used for both DCS and GSM.
US Patent Application No. US20060040700, A1 describes a method and apparatus for selecting cells in a mobile telecommunications system, the system comprising a network of a plurality of cells of a Universal Mobile Telecommunications System, UMTS, and a network of a plurality of cells of a second Radio Access Technology, RAT, the method comprising, at a user equipment device when in UMTS mode, flagging in a neighboring cell list stored on the user equipment device information for a cell of a second RAT which is known to be unsuitable for selection. The patent application provides strategies for User Equipment measurement procedures, available in UMTS idle mode and during cell reselection to a GSM cell. The GSM neighboring cell lists may contain GSM cells that are barred and which are to be removed from the lists until expiry of a time interval, Tbarred, or there may be a list for containing details of cells which are barred and details of the barred/unsuitable cell is added to this list. The barred cells may keep their indices in the list but no measurement is performed; i.e. no scan at the frequency of that cell is made.
U.S. Pat. No. 6,970,702 describes a system for and method of cellular telephone system monitoring. It includes a cellular switch which is remotely accessed and placed in a call monitor mode. A GPS receiver is connected to a mobile telephone via an interface unit. Call performance information, e.g. signal strength, BER and call events, are recorded at the switch and downloaded to a remote computer. GPS location information is transmitted by the mobile telephone and received by the remote computer via the switch. The computer receives and stores the recorded call and GPS information and graphically displays this information, along with a map indicating the location of the mobile telephone.
To achieve improved performance levels, cellular telephone service providers position antennas in geographically desirable locations and tune and/or direct antennas in optimal ways. While radio frequency, RF, engineering tools exist to help properly position individual cellular telephone cell site antennas and configure overall cellular systems, the only effective way of actually determining whether the cellular antennas and their tuning/positioning have been properly accomplished is to perform field tests with a cellular telephone. Typically, such field tests are accomplished with drive tests wherein an RF or cellular engineer drives a vehicle around in a designated area while making one or more telephone calls using his mobile cellular telephone. During the drive test, the RF engineer monitors call performance by noting call drops, for example, and/or collecting actual downlink data such as signal strength directly from the mobile telephone.
The RF engineer then returns to his office where he uploads the collected data to, e.g., a computer spreadsheet program, and attempts to combine or correlate this data with data from the same time period as the drive test, obtained from the cellular system's controller or switch such as a Mobile Telephone Switching Office, MTSO, or Mobile Switching Center, MSC. The data from the switch might include signal strength, bit error rate, BER, and other call events, such as call handoffs, during the time that the RF engineer was performing the drive test. Once an analysis of the combined data is complete and changes to the cellular system are made, if necessary, the RF engineer will typically return to the drive-test area to confirm that the changes made have improved overall system performance. The iterative procedure of drive testing, system changing, and subsequent drive-test confirmation continues as long as believed that improved service, e.g. coverage and continuity, can be achieved.
While drive-tests might provide an effective method for confirming and testing system performance, it is also an extremely inefficient exercise, in terms of time, for an RF engineer. Instead of spending valuable time making calculations and studying data to optimize a cellular system in an office setting, the RF engineer might spend a great deal of his working time on driving to, around and from an area under investigation.
In U.S. Pat. No. 6,970,702 persons other than RF engineers perform cellular system drive-tests.